The cesium-beam standard used for this measurement could be operated for only short periods, so the uncertainty of Lyon¿s measurement was too large for it to serve as the basis for a new definition.

“The optical clock community is strongly motivated to obtain the best possible set of measurements before the SI second is ...

・The International System of Units (SI) redefined the second based on the cesium-133 atom’s vibrations: “The duration of 9,192,631,770 periods of the radiation corresponding to the ...

"The second… is defined by taking the… transition frequency of the caesium-133 atom, to be 9192631770 when expressed in the unit Hz, which is equal to s⁻¹." If you're confused, let me ...

A common kind of atomic clock uses a form of cesium called cesium-133. ... In other words, in a single second, a cesium-133 atom transitions some 9,192,631,770 times.

(waves ticking) (air whooshes) Today, a second is officially defined by counting the oscillations of the primary resonant frequency of a Cesium-133 atom. That's over 9 billion oscillations per second.

And the future of cesium-133 clocks themselves remains murky, especially as researchers develop and perfect even more reliable timekeepers like NIST’s experimental Ytterbium clock, a device that ...

The idea of using light frequencies to measure time was first proposed in 1873 by James Clerk Maxwell and since 1968 the standard measure of time, the second, has been defined based on the frequency ...

To do this, a high-powered laser light is trained on an atom of cesium-133, which subsequently excites its electrons into phasing between energy levels at exactly 9,192,631,770 vibrations over a ...

In 1967, the second was defined as the equivalent of the time it takes for a cesium 133 atom to oscillate 9,192,631,770 times between the two energy states.

The 5071B cesium atomic clock from Microchip Technology lets data centers or telecoms towers operate ... has been defined based on the frequency of light emitted by the cesium-133 atom. ...